This invention relates to the fabrication of microstructures for use in assays.
There is considerable interest in the production of microstructures for the testing and quantitation of species, for the monitoring of binding reactions between molecules, for the manufacture of micro-fluidic systems for drug discovery, for genetic analysis and for clinical diagnostic assays. In particular, there is increasing interest in the development of smaller micro-plates for chemical synthesis, for combinatorial chemistry, for high throughput screening assays, and for binding reactions. The traditional 96-well microtitre plate is being superseded by systems in which there are a greater number, e.g. up to 2304, wells on a plate; see Lemmo et al, Anal. Chem. (1997) 69:543-551.
Plates with greater numbers of small wells have considerable advantages, including the use of lower amounts of expensive reagents and the greater number of reactions that can be screened on one plate, thus reducing costs and maximising throughput. It is also desirable to produce microstructures for valving and pumping liquids on the same device.
According to one aspect of the present invention, a method for the manufacture of a microstructure comprises the use of screen-printed layers over a sheet material. According to a second aspect of the invention, a microstructure is obtained by photoresist technology.
The methods of the invention allow the production of microstructures, on a plastics substrate, in large volume at low cost. Depending on the technique that is used, they allow the construction of microstructures having resolution down to 3-5 xcexcm. In one particular embodiment, the microstructure is in the form of a microtitre plate array, into which chemicals, reagents or other materials are dispensed for the carrying out of reactions of interest to the pharmaceutical and diagnostic industry. A device made by this method may be used for analysis of liquid samples, for the detection of binding events between binding partners, for drug discovery applications and for combinatorial chemistry and other reactions.